公开(公告)号：JP2002351417A

公开(公告)日：2002-12-06

申请号：JP2001156177

申请日：2001-05-24

Applicant: IBM

Inventor： SAKURAI TAKAAKI ,  WATANABE YOSHIAKI ,  YANA TOSHIYUKI ,  KARUBE SATOSHI

IPC: G02F1/133 ,  G09G3/20 ,  G09G3/36 ,  H02M3/155

Abstract: PROBLEM TO BE SOLVED: To provide a liquid crystal driving power supply circuit in which a driving power supply voltage to be supplied to a driver circuit is precisely generated by employing a low precision reference voltage generating circuit. SOLUTION: A driving power supply circuit 11 consists of a DC/DC converter 34 which generates a voltage having a size based on oscillating signals VOUT from a power supply voltage Vcc of the circuit 11 and outputs the generated voltage as a driving power supply voltage Vdcdc , a stable power supply circuit 60 which generates a most significant reference potential Vref H used to generate a gradation voltage in a driver circuit, a comparison section 46 which computes the difference between the voltage Vdcdc and the potential Vref H and outputs the computed difference as a difference voltage, an internal reference voltage generating section 42 which generates an internal reference voltage VREF having a prescribed size, an error amplifying section 44 which computes the difference between a reference voltage that is determined by the generated voltage VREF and the difference voltage and a PWM converting section 32 which outputs the signals VOUT in accordance with the difference.

公开(公告)号：JP2001337730A

公开(公告)日：2001-12-07

申请号：JP2000146376

申请日：2000-05-18

Applicant: IBM

Inventor： SAKURAI TAKAAKI ,  WATANABE YOSHIAKI ,  YOSHIKAWA HIROSHI

IPC: G09G3/36 ,  G05F1/56 ,  G05F3/22 ,  G09G3/20

Abstract: PROBLEM TO BE SOLVED: To provide a power supply circuit which reduces total power consumption for the circuit. SOLUTION: R1-Rm-1 are internal resistance of a TFT driver. Q1-Qm are active elements such as transistors or the like, and control Vout (1) voltage, Vout (2) voltage ... Vout (m) voltage by changing their conductance. Output voltage Vout (1) - Vout (m) are compared with voltage V1-Vm given from a voltage regulating circuit by differential amplifiers U1-Um which have functions of feedback circuit and calculating circuit, and are controlled to be same voltage as the reference voltage by each transistor. The total power consumption for the circuit can be reduced because the active elements are inserted between plural output nodes of which required voltage balance are predetermined, and by controlling the conductance of the elements, the required reference voltage is supplied to each node.

公开(公告)号：JP2002244621A

公开(公告)日：2002-08-30

申请号：JP2001030240

申请日：2001-02-06

Applicant: IBM

Inventor： WATANABE YOSHIAKI ,  SAKURAI TAKAAKI ,  KIKUCHI YASUTO

IPC: G02F1/133 ,  G09G3/20 ,  G09G3/36

Abstract: PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of reducing flickers irrespective of any display pattern. SOLUTION: In a 1st frame, driving voltages with polarities defined according to random numbers in the unit of rows are applied, and in the following 2nd frame, the driving voltages of the inverted polarities of those in the 1st frame are applied. The polarity patterns are alternately repeated.